Merge #13953: fix deprecation in bitcoin-util-test.py

49e56625aa fix deprecation in bitcoin-util-test.py (Isidoro Ghezzi)

Pull request description:

  To avoid:

  $ make check
  {…omissis…}
  Running test/util/bitcoin-util-test.py...
  /usr/local/bin/python3.7 ../test/util/bitcoin-util-test.py
  ../test/util/bitcoin-util-test.py:31: DeprecationWarning: This method will be removed in future versions.  Use 'parser.read_file()' instead.
  config.readfp(open(os.path.join(os.path.dirname(__file__), "../config.ini"), encoding="utf8"))

  $ python3 --version
  Python 3.7.0

Tree-SHA512: eafed629b64ae32b0b84520bb9b430204cba38d426dab1b3946a92c758c7d599aacc2798ab6e126808a6c7515ff20eb4ecc635b3e424f4c8903105438f817297

test/util/bitcoin-util-test.py

@@ -28,7 +28,7 @@ import sys
 def main():
     config = configparser.ConfigParser()
     config.optionxform = str
-    config.readfp(open(os.path.join(os.path.dirname(__file__), "../config.ini"), encoding="utf8"))
+    config.read_file(open(os.path.join(os.path.dirname(__file__), "../config.ini"), encoding="utf8"))
     env_conf = dict(config.items('environment'))
 
     parser = argparse.ArgumentParser(description=__doc__)